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"All that is",
This review is from: Cosmos (Mass Market Paperback)
As one of the great astronomer-writers of the Twentieth Century, Carl Sagan was extraordinarily communicative with the non-scientific public, able and willing to take the time and trouble to break down the mysteries of the universe into comprehensible fragments. The purpose of this book, which can be considered a companion to the acclaimed television series, is to explain what we know about the universe from a cosmological perspective and why we need to know more about it.
Physicists often talk of the unity of the branches of physics: the interrelation and application of mechanics, thermodynamics, electricity and magnetism, and optics to the motion of everything from galaxies to subatomic particles. Similarly, Sagan's major theme is the unity of cosmology with the natural and physical sciences that define what we know about the Earth. Does the stifling, carbon dioxide-choked atmosphere of Venus imply anything about the greenhouse effect on Earth? Was a nearby cosmic explosion called a supernova indirectly responsible for the disappearance of the dinosaurs? What would be the biological consequences for the survivors of a global nuclear war? The answers to these questions are vital to the continuation of life as we know it.
Sagan also identifies cosmology with its own history. He lavishes reverent detail on the ancient Greek and Alexandrian study of the stars and planetary motions, the pioneering work by the Renaissance scientists Brahe, Kepler, Copernicus, Huygens, and others, and the men who revolutionized science with the formulation of laws of motion, Newton and Einstein.
The scope of "Cosmos" is tremendous, from the farthest expanses of the universe containing a hundred billion galaxies in addition to our own Milky Way, at the end of a spiraling arm of which our solar system is located; down to the lone electron circling the nucleus of a hydrogen atom, the most plentiful single entity in the cosmos and the source of everything we know, love, and are. In between there is discussion of the unmanned spacecraft expeditions to investigate "our" planets: Mars with its boulder-strewn, desert-like terrain; the gaseous giant Jupiter; Io, a Jovian moon of incredible redness, spotted with volcanic orifices and resembling an unappealing sauce-covered meatball; Saturn with its ice rings. Would these worlds contain life? Using what we know about the evolution of life on Earth, Sagan hypothesizes how different types of lifeforms might develop on worlds with different environments.
Even a casual interest in cosmology requires a fascination with astronomical distances and unthinkably long spans of time in which a human lifetime is but a blink of an eye. However, Sagan seems to write also for those who would rather relate cosmic arcana to familiar terms, and in this sense he is a grand entertainer: A thought experiment that provides a simple but fanciful illustration of the concept of black holes uses the tea party scene in "Alice in Wonderland" as a setting. "Cosmos" neither complicates unnecessarily nor insults your intelligence; very few "popular" science books will capture your imagination so well.